USRP Hardware Driver and USRP Manual: Daughterboards (2024)

The following contains interesting notes about each daughterboard. Eventually, this page will be expanded to list out the full properties of each board as well.

Basic RX and LFRX

The Basic RX and LFRX boards have four modes of operation:

• Antenna Mode A: real signal from antenna RXA
• Antenna Mode B: real signal from antenna RXB
• Antenna Mode AB: complex signal using both antennas (IQ)
• Antenna Mode BA: complex signal using both antennas (QI)

The way in which you select the mode depends on the USRP type.

The X300 series will create subdevices 0 and 1 for each BasicRX or LFRX board. The default is to make a channel for each subdevice. That can be controlled by setting the subdev spec:

The antenna mode is selected for each channel using the antenna API:

On the USRP2, the N200 series, the B100 series, the E100, and the USRP1 the mode depends on the subdev spec applied:

The boards have no tunable elements or programmable gains. Through the magic of aliasing, you can down-convert signals greater than the Nyquist rate of the ADC.

BasicRX Bandwidth:

• For Real-Mode (Antenna Mode A or B): 250 MHz
• For Complex (Antenna Mode AB or BA): 500 MHz

LFRX Bandwidth:

• For Real-Mode (Antenna Mode A or B): 33 MHz
• For Complex (Antenna Mode AB or BA): 66 MHz

Basic TX and LFTX

The Basic TX and LFTX boards have 4 modes of operation:

• Antenna Mode A: real signal from antenna TXA
• Antenna Mode B: real signal from antenna TXB
• Antenna Mode AB: complex signal using both antennas (IQ)
• Antenna Mode BA: complex signal using both antennas (QI)

The boards have no tunable elements or programmable gains. Through the magic of aliasing, you can up-convert signals greater than the Nyquist rate of the DAC.

BasicTX Bandwidth:

• For Real-Mode (Antenna Mode A or B): 250 MHz
• For Complex (Antenna Mode AB or BA): 500 MHz

LFTX Bandwidth:

• For Real-Mode (Antenna Mode A or B): 33 MHz
• For Complex (Antenna Mode AB or BA): 66 MHz

DBSRX

The DBSRX board has 1 quadrature frontend. It defaults to direct conversion but can use a low IF through lo_offset in uhd::tune_request_t.

Receive Antennas: J3

• Frontend 0: Complex baseband signal from antenna J3

The board has no user selectable antenna setting.

Receive Gains:

• GC1, Range: 0-56dB
• GC2, Range: 0-24dB

Bandwidth: 8 MHz - 66 MHz

Sensors:

• lo_locked: boolean for LO lock state

DBSRX2

The DBSRX2 board has 1 quadrature frontend. It defaults to direct conversion, but can use a low IF through lo_offset in uhd::tune_request_t.

Frequency Range: 800 MHz to 2.3 GHz

Receive Antennas: J3

• Frontend 0: Complex baseband signal from antenna J3

The board has no user-selectable antenna setting.

Receive Gains:

• GC1, Range: 0-73dB
• BBG, Range: 0-15dB

Bandwidth (Hz): 8 MHz-80 MHz

Sensors:

• lo_locked: boolean for LO lock state

Notes:

• When used in the X3x0, set the daughterboard clock rate to 100 MHz (see Device Configuration through address string)

RFX Series

The RFX Series boards have 2 quadrature frontends: Transmit and Receive. Transmit defaults to low IF, and Receive defaults to direct conversion. The IF can be adjusted through lo_offset in uhd::tune_request_t.

The RFX Series boards have independent receive and transmit LO's and synthesizers allowing full-duplex operation on different transmit and receive frequencies.

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

• Frontend 0: Complex baseband signal for selected antenna

The user may set the receive antenna to be TX/RX or RX2. However, when using an RFX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Receive Gains: PGA0, Range: 0-70dB (except RFX400 range is 0-45dB)

Bandwidth:

• RX: 40 MHz
• TX: 40 MHz

Sensors:

• lo_locked: boolean for LO lock state

XCVR 2450

Note: The XCVR2450 is not compatible with the X3x0-Series.

The XCVR2450 has 2 quadrature frontends, one transmit, one receive. Transmit and Receive default to direct conversion but can be used in low IF mode through lo_offset in uhd::tune_request_t.

The XCVR2450 has a non-contiguous tuning range consisting of a high band (4.9-6.0 GHz) and a low band (2.4-2.5 GHz).

Transmit Antennas: J1 or J2

Receive Antennas: J1 or J2

• Frontend 0: Complex baseband signal for selected antenna

The XCVR2450 uses a common LO for both receive and transmit. Even though the API allows the RX and TX LOs to be individually set, a change of one LO setting will be reflected in the other LO setting.

The XCVR2450 does not support full-duplex mode, attempting to operate in full-duplex will result in transmit-only operation.

Transmit Gains:

• VGA, Range: 0-30dB
• BB, Range: 0-5dB

Receive Gains:

• LNA, Range: 0-30.5dB
• VGA, Range: 0-62dB

Bandwidths:

• RX: 15 MHz, 19 MHz, 28 MHz, 36 MHz; (each +-0, 5, or 10%)
• TX: 24 MHz, 36 MHz, 48 MHz

Sensors:

• lo_locked: boolean for LO lock state
• rssi: float for rssi in dBm

WBX Series

Features:

• 2 quadrature frontends (1 transmit, 1 receive)
  • Defaults to direct conversion
  • Can be used in low IF mode through lo_offset with uhd::tune_request_t
• Independent receive and transmit LO's and synthesizers
  • Allows for full-duplex operation on different transmit and receive frequencies
  • Can be set to use Integer-N tuning for better spur performance with uhd::tune_request_t

Frequency Range: 50 MHz to 2.2 GHz

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

• Frontend 0: Complex baseband signal for selected antenna
• Note: The user may set the receive antenna to be TX/RX or RX2. However, when using a WBX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Transmit Gains: PGA0, Range: 0-25dB

Receive Gains: PGA0, Range: 0-31.5dB

Bandwidths:

• WBX: 40 MHz, RX & TX
• WBX-120: 120 MHz, RX & TX

Sensors:

• lo_locked: boolean for LO lock state

SBX Series

Features:

• 2 quadrature frontends (1 transmit, 1 receive)
  • Defaults to direct conversion
  • Can be used in low IF mode through lo_offset with uhd::tune_request_t
• Independent receive and transmit LO's and synthesizers
  • Allows for full-duplex operation on different transmit and receive frequencies
  • Can be set to use Integer-N tuning for better spur performance with uhd::tune_request_t

Frequency Range: 400 MHz to 4.4 GHz

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

• Frontend 0: Complex baseband signal for selected antenna
• Note: The user may set the receive antenna to be TX/RX or RX2. However, when using an SBX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Transmit Gains: PGA0, Range: 0-31.5dB

Receive Gains: PGA0, Range: 0-31.5dB

Bandwidths:

• SBX: 40 MHz, RX & TX
• SBX-120: 120 MHz, RX & TX

Sensors:

• lo_locked: boolean for LO lock state

LEDs:

• All LEDs flash when daughterboard control is initialized
• TX LD: Transmit Synthesizer Lock Detect
• TX/RX: Receiver on TX/RX antenna port (No TX)
• RX LD: Receive Synthesizer Lock Detect
• RX1/RX2: Receiver on RX2 antenna port

CBX Series

Features:

• 2 quadrature frontends (1 transmit, 1 receive)
  • Defaults to direct conversion
  • Can be used in low IF mode through lo_offset with uhd::tune_request_t
• Independent receive and transmit LO's and synthesizers
  • Allows for full-duplex operation on different transmit and receive frequencies
  • Can be set to use Integer-N tuning for better spur performance with uhd::tune_request_t

Frequency Range: 1.2 GHz to 6 GHz

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

• Frontend 0: Complex baseband signal for selected antenna
• Note: The user may set the receive antenna to be TX/RX or RX2. However, when using a CBX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Transmit Gains: PGA0, Range: 0-31.5dB

Receive Gains: PGA0, Range: 0-31.5dB

Bandwidths:

• CBX: 40 MHz, RX & TX
• CBX-120: 120 MHz, RX & TX

Sensors:

• lo_locked: boolean for LO lock state

LEDs:

• All LEDs flash when daughterboard control is initialized
• TX LD: Transmit Synthesizer Lock Detect
• TX/RX: Receiver on TX/RX antenna port (No TX)
• RX LD: Receive Synthesizer Lock Detect
• RX1/RX2: Receiver on RX2 antenna port

UBX Series

Features:

• 2 quadrature frontends (1 transmit, 1 receive)
  • Defaults to direct conversion
  • Can be used in low IF mode through lo_offset with uhd::tune_request_t
• Independent receive and transmit LO's and synthesizers
  • Allows for full-duplex operation on different transmit and receive frequencies
  • Can be set to use Integer-N tuning for better spur performance with uhd::tune_request_t

Frequency Range: 10 MHz to 6 GHz

Transmit Antennas: TX/RX

Receive Antennas: TX/RX or RX2

• Frontend 0: Complex baseband signal for selected antenna
• Note: The user may set the receive antenna to be TX/RX or RX2. However, when using a UBX board in full-duplex mode, the receive antenna will always be set to RX2, regardless of the settings.

Transmit Gains: PGA0, Range: 0-31.5dB

Receive Gains: PGA0, Range: 0-31.5dB

Bandwidths:

• UBX: 40 MHz, RX & TX
• UBX-160: 160 MHz, RX & TX

Sensors:

• lo_locked: boolean for LO lock state

LEDs:

• LOCK: Synthesizer Lock Detect
• TX/RX TXD: Transmitting on TX/RX antenna port
• TX/RX RXD: Receiving on TX/RX antenna port
• RX2 RXD: Receiving on RX2 antenna port

Notes:

• When used in the X300/X310 at frequencies below 1 GHz, it is necessary to reduce the daughterboard clock rate to 20 MHz to achieve phase synchronization and best RF performance (see Device Configuration through address string).
• The LO lock sensor for the UBX can intermittently fail to report True. The mitigation depends on whether tuning is done using timed commands or not.
  • If not using timed commands, a temperature compensation mode can be enabled to help the LO to lock. It may also increase the tuning time, though, which is why the default is to disable the temperature compensation mode. To enable the temperature compensation mode, identify the property tree path to the daughterboard, and set the temp_comp_mode to "enabled":

    // Assume DEV is a valid device, and we are talking to the UBX in motherboard 0

    // in slot A:

    DEV->get_tree()->access<std::string>("/mboards/0/rx_frontends/A/temp_comp_mode/value")

    .set("enabled");

  • If using timed commands, the LO uses a map to choose the appropriate VCO band. There is a calibration for the map that can be run by setting the calibrate_vco_map property to true. It is done independently for TX and RX:

    // Assume DEV is a valid device, and we are talking to the UBX in motherboard 0

    // in slot A:

    DEV->get_tree()->access<bool>("/mboards/0/rx_frontends/A/calibrate_vco_map")

    .set(true);

    DEV->get_tree()->access<bool>("/mboards/0/tx_frontends/A/calibrate_vco_map")

    .set(true);

  • The VCO maps for each LO can be accessed and controlled independently. This allows users to calibrate the maps for a particular daughterboard in their environment so the same VCO is always used for a given frequency. This may be necessary to maintain the same phase offset between channels across power cycles. The maps can be accessed via the vco_map property:

    // Assume DEV is a valid device, and we are talking to the UBX in motherboard 0

    // in slot A:

    auto rx_lo1_map = DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/rx_frontends/A/LO1/vco_map")

    .get();

    auto rx_lo2_map = DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/rx_frontends/A/LO2/vco_map")

    .get();

    auto tx_lo1_map = DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/tx_frontends/A/LO1/vco_map")

    .get();

    auto tx_lo2_map = DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/tx_frontends/A/LO2/vco_map")

    .get();

    DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/rx_frontends/A/LO1/vco_map")

    .set(rx_lo1_map);

    DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/rx_frontends/A/LO2/vco_map")

    .set(rx_lo2_map);

    DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/tx_frontends/A/LO1/vco_map")

    .set(tx_lo1_map);

    DEV->get_tree()->access< std::map<int,uhd::range_t> >("/mboards/0/tx_frontends/A/LO2/vco_map")

    .set(tx_lo2_map);

TwinRX

Features:

• 2 super-heterodyne frontends (2 receive, 0 transmit)
  • Digital IF of +/- 50 MHz
• Supports sharing one channel's LO to the other or the use of an external LO
  • Allows multiple channels and daughterboards to be frequency and phase synchronized

Frequency Range: 10 MHz to 6 GHz

Receive Antennas: RX1 and RX2

Receive Gain: 0-93dB

The TwinRX daughterboard only works with the X300/X310 motherboards, and requires a master clock rate of 200 MHz.

More information:

• TwinRX Daughterboard

TVRX

The TVRX board has 1 real-mode frontend. It is operated at a low IF.

Receive Antennas: RX

• Frontend 0: real-mode baseband signal from antenna RX

Receive Gains:

• RF, Range: -13.3-50.3dB (frequency-dependent)
• IF, Range: -1.5-32.5dB

Bandwidth: 6 MHz

TVRX2

The TVRX2 board has 2 real-mode frontends. It is operated at a low IF.

Frequency Range: 50 MHz to 860 MHz

Receive Frontends:

• Frontend RX1: real-mode baseband from antenna J100
• Frontend RX2: real-mode baseband from antenna J140

Note: The TVRX2 has always-on AGC; the software controllable gain is the final gain stage which controls the AGC set-point for output to ADC.

Receive Gains:

• IF, Range: 0.0-30.0dB

Bandwidth: 1.7 MHz, 6 MHz, 7 MHz, 8 MHz, 10 MHz

Sensors:

• lo_locked: boolean for LO lock state
• rssi: float for measured RSSI in dBm
• temperature: float for measured temperature in degC

Notes:

• The TVRX2 requires a 64 MHz, 100 MHz or 200 MHz reference clock. On the X3x0, set the daughterboard clock rate accordingly (see Device Configuration through address string), typically to 100 MHz.

E310 MIMO XCVR board

Please refer to Daughterboard notes.

N310 XCVR board

Please refer to N310-specific Features.

ZBX XCVR board

Features:

• Dual channel transceivers
• TX/RX 0 and RX 1 antenna ports per channel
• Frequency Range: 1 MHz to 8 GHz
• Relative Gain Range: 0 - 60 dB (RX gain range reduced below 500 MHz)

The ZBX daughterboard only works with the X410 motherboard.

More information:

• ZBX Daughterboard

FBX XCVR board

Features:

• Quad channel transceivers
• TX/RX 0 and RX 1 antenna ports per channel
• Frequency Range: 30 MHz to 4 GHz
• Relative Gain Range: 0 dB (no gain control)

The FBX daughterboard only works with the X440 motherboard.

More information:

• FBX Daughterboard

Daughterboard reference clock

The USRP motherboard provides a reference clock to the daughterboards, which the daughterboards will use to generate LO signals or anything else that requires a reference clock.

The X3x0 has a programmable reference clock, which might have to be changed depending on various applications (see the daughterboard sections above). However, it can provide only one daughterboard clock per device, which can lead to conflicts. It might not be possible to use a specific daughterboard together with all others.

DBSRX - Modifying for other boards that USRP1

Due to different clocking capabilities, the DBSRX will require modifications to operate on a non-USRP1 motherboard. On a USRP1 motherboard, a divided clock is provided from an FPGA pin because the standard daughterboard clock lines cannot provided a divided clock. However, on other USRP motherboards, the divided clock is provided over the standard daughterboard clock lines.

Step 1: Move the clock configuration resistor

Remove R193 (which is 10 Ohms, 0603 size), and put it on R194, which is empty. This is made somewhat more complicated by the fact that the silkscreen is not clear in that area. R193 is on the back, immediately below the large beige connector, J2. R194 is just below, and to the left of R193.

The silkscreen for R193 is ok, but for R194, it is upside down, and partially cut off. If you lose R193, you can use anything from 0 to 10 Ohms there.

Step 2: Burn a new daughterboard id into the EEPROM

With the daughterboard plugged-in, run the following commands:

cd <install-path>/lib/uhd/utils./usrp_burn_db_eeprom --id=0x000d --unit=RX --args=<args> --slot=<slot>

• <args> are device address arguments (optional if only one USRP device is on your machine)
• <slot> is the name of the daughterboard slot (optional if the USRP device has only one slot)

RFX - Modify to use motherboard oscillator

Older RFX boards require modifications to use the motherboard oscillator. If this is the case, UHD software will print a warning about the modification. Please follow the modification procedures below:

• Step 1: Disable the daughterboard clocks**

Move R64 to R84. Move R142 to R153.

• Step 2: Connect the motherboard blocks

Move R35 to R36. Move R117 to R115. These are all 0-Ohm, so if you lose one, just short across the appropriate pads.

• Step 3: Burn the appropriate daughterboard ID into the EEPROM

With the daughterboard plugged in, run the following commands: :

cd <install-path>/lib/uhd/utils./usrp_burn_db_eeprom --id=<rx_id> --unit=RX --args=<args> --slot=<slot>./usrp_burn_db_eeprom --id=<tx_id> --unit=TX --args=<args> --slot=<slot>

• <rx_id> choose the appropriate RX ID for your daughterboard
  • RFX400: 0x0024
  • RFX900: 0x0025
  • RFX1800: 0x0034
  • RFX1200: 0x0026
  • RFX2400: 0x0027
• <tx_id> choose the appropriate TX ID for your daughterboard
  • RFX400: 0x0028
  • RFX900: 0x0029
  • RFX1800: 0x0035
  • RFX1200: 0x002a
  • RFX2400: 0x002b
• <args> are device address arguments (optional if only one USRP device is on your machine)
• <slot> is the name of the daughterboard slot (optional if the USRP device has only one slot)